Collector of Q2 is connected to the base of transistor Q6 and as result transistor Q6 gets switched ON. LEDs D1, D2 and D3 provide a visible indication of the current water level.When the water level goes below medium, transistor Q2 gets switches OFF and its collector goes positive. Resistors R1, R2, R3 limit the bases current of corresponding transistors while resistors R4, R5, R6 limit their collector current. When the water level rises and touches the probes the corresponding transistors gets biased and switches ON. When water level is below the quarter level probes A, B and C are open and the transistor Q1, Q2 and Q3 remains OFF. The level sensing part of the circuit is built around transistors Q1, Q2 and Q3.
Probe D is positioned at the bottom level of the tank while probes A, B and C are placed at full, half and medium levels of the tank respectively.
#Use tank circuit as timer full#
The circuit is completely automatic which starts the pump motor when the water level in the over head tank goes below a preset level and switches OFF the pump when the water level in the over head tank goes above the full level. The circuit uses 6 transistors, 1 NE555 timer IC, a relay and few passive components. If it does, the relay must be replaced by a 9V one.A simple but very reliable and effective water level controller circuit diagram is shown here. The circuit is connected to a 12 VDC source, but the voltage can be changed to 9 VDC without problems.The sensors can be small, well-polished metal rods connected to the circuit by thin conductors.Water is used as the conductive path for electricity between the sensors, but since little voltage and current are used, it is not dangerous.2 4.7uF (microfarads) electrolytic capacitors (C3, C4).1 2 poles, double contact, 12 volts relay (RL), Capable of conducting the current of the water pump.1 1N4001 or similar rectifier diode (D2).1 1N4148 or similar rectifier diode (D1).1 2SD882, NTE184 or similar NPN bipolar transistor (Q2).1 BC547 or similar NPN bipolar transistor (Q1).List of components of the water tank level controller circuit Thus, the process of filling and emptying the water is constantly repeated. The water level drops when water consumption starts.ġ – When the three sensors are still underwater (tank full), the relay is active and the pump is not connected (it does not pump water into the tank)Ģ – When the upper sensor is no longer underwater, the relay is still active and the pump still does not work (it does not pump water into the tank)ģ – When the second sensor is no longer underwater, the relay is deactivated and the pump is switched on (water is pumped into the tank) These transistors go into saturation and activate the relay, which in turn disconnects the water pump, ceasing to fill the tank. This multivibrator delivers a continuous square wave at its output, which is rectified (half-wave rectification) and applied to the set of two cascaded transistors. In this case, the 555 outputs a high voltage level (approximately 10 to 11 volts) that, after passing through the network of capacitors, diode and resistance, does not saturate the transistors.Ģ – When the water reaches the level of the second sensor, there is no change and the pump is still active filling the tank.ģ – When the water reaches the level of the third sensor (the upper sensor), the 555 integrated circuit starts its operation as an astable multivibrator. See that the pump is working (its normal state) when the relay is not active. In this case the pump is connected and pumping water to the elevated tank. How the automatic water level controller circuit works? When the water level rises:ġ – When the tank is low or has no water, no sensor touches the liquid or only the lower sensor does. The tank has 3 sensors that indicate the amount of water in the tank to the controller circuit. This pump activates itself whenever the water level is below an already set level and deactivates when it reaches a maximum level, also set. To bring the water from the ground level to the tank, a pump (motor) is used. In order for the pressure to increase and be able to reach everywhere, it is necessary to place an elevated tank and thus the water is distributed by gravity.
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